Internal-combustion engine



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O.'H. ERICKSON INTERNAL COMBUSTION ENGINE Filed April 9, 1927 Z Z W/ Patented Ang. 13, M229.

raras OSCAR H. ERCKSOQ", GF 'UYALL'UP, WASHNGTON.

INTERNAL-COMBUSTION ENGINE.

Application filed April 9, 1927. Serial No. 182,271.

This invention relates to internal combustion engines and has special reference to engines belonging to the two-stroke type. The objects of the invention are to provide such -an engine which will have a high compression and a high fuel eiiiciency, and which will improve the thermodynamic qualities of such engines. Further objects are to provide special means for attaining a preliminary compression, and a special means for controlling and transferring said compression to they engine.

I attain these and other objects by the devices, mechanisms, and arrangements illustrated in the accompanying drawings in which:

Fig. 1 is a vertical longitudinal section of an engine constructed in accordance with my design and having two working cylinders; Fig. 2 is a transverse section thereof on the line 2-2 in Fig. 1; Fig. 3 is a cross sect-ion thereof on the line 3-3 in Fig. 1; Fig. 4 is a vertical crossv sectional view on the line 4-4 in Fig. 1; Fig. 5 is a horizontal cross section of the sleeve and its cam frame, taken on the line 5-5 in Fig. 4; Figs 6 and 7 are horizontal sections of the engine taken on the line 6 6, 7-7, respectively in Figs. 1, 2 and 3, except that in Fig. 7 the positions of all the pistons are such that the lefthand working piston is at the lower end of its stroke and the right-hand working piston is at the upper end of its stroke.

Similar numerals of reference refer to similar parts throughout the several views.

This engine comprises several identical units, two of which are shown in the drawings, it being fully understood that other such units may be added thereto as needed. The description of one such unit will be understood to apply to all. ln the drawings, however, two such units are shown combined together into a single structure as it is understood that this arrangement would be the most economical in construction.

Referring to the drawings, it will be seen that the shaft 1 is mounted in suitable bearings 2 and has two working cranks 3, between the said bearings, one such crank 3 being adjacent to each of said bearings 2. The vshaft 1 is also provided with two intermediate cranks 4, which are set at an angle to the first `cranks 3, said angle being such that the piston connected to the second crank 4 is three-eighths of the stroke in advance of the piston connected to the first crank 8 when the said lirst piston is beginning its stroke. These second cranks 4 are immediately adjacent to first cranks 3. Two specially shaped cams 5 are mounted between the two said cranks 4, each of which operates a sleeve in which thesecond pistonv works. The positions of the said cams 5 on the shaft l, relatively to the said second cranks 4, are

ysuch that when the corresponding piston,

connected to the said crank 4, is at the upper end of its stroke the sleeve is one-quarter of its stroke in advance of the said piston. It will therefore be seen that the shaft l receives its working force from the cranks 3, immediately adjacent to the bearings 2, and that the small amount of energy needed to operate the second piston and the sleeve is transmitted thereto through the cranks 4 and the cams 5, which are further removed from the bearings 2. The bending strains, therefore, on the shaft will be kept low since the larger portion of the bending force will be applied close to the bearings 2. The relative position of the two sets of cranks in the above description are such that the main pistons occupy corresponding opposite positions at all times.

Referring to the several drawings it will be seen that each unit of the engine is provided with two cylinders, a main cylinder 6 and a supplementary cylinder 7. The supplementary cylinder 7 is of smaller diameter than the main cylinder 5 and is in close connection therewith. rlhe main cylinder 6 is surrounded yby'suitable jacket 8 forming a water chamber, by means of which the working cylinder 6 is kept cool. The head 9 closes the cylinder 6 and 7, at the upper end, and is suitably water jacketed. The head 9 is provided with a cylindrical projection 10 which enters centrally into the upper end of the main working cylinder 6, but is of smaller diameter', thereby forming an annular space 11 surrounding this projection 10. A suitable spark plug 12 passes through this projection 10 into the cylinder 6. A. filler plug 13 is fitted into the upper end of the supplementary cylinder 7 and is provided with a cylindrical projection 14, of smaller diameter, which extends down into the cylinder 7 and forms an annular space 15 between it and the wall of the cylinder.

The main piston 16 is provided with the usual connecting rod 17, by which it is connected to the main crank 3 of the shaft 1. This piston 16 is of special shape, as shown in Figs. 1 and 2, being provided with a hollow cylindrical cuff or wall 18 extending upward from the upper surface of the piston, said wall 18 entering the said annular space 11 and forming an explosion chamber therewith. This annular cuff or wall 18 is pierced by several openings 19 and 20 clearly seen in Figs. 6 and 7. The openings 19 thereof pass outward laterally and are adapted to register with the exhaust ports 21 in the wall of the cylinder 6, as hereinafter described, when the said piston 16 is at the lower end of its stroke (see left pist-on in Fig. 7). The said exhaust ports 21, in the wall of the cylinder 6, connect with suitable manifolds 22 leading to the muffler or other exhaust passage of the engine. The above-mentioned openings 20, in the piston cuff 18, are positioned at right angles to the openings 19, on the side adjacent to the supplementary cylinder 7, and areadapted to register with the inlet or pressure port 23 in the wall of the cylinder 6 when the piston 16 is at the central part of the stroke, as hereinafter described. The port 23 leads through the wall separating the cylinders 6 and 7.

A sleeve 24 is mounted in the second or supplementary cylinder 7 and is provided with a pressure port 25 registering with the above-described port 23, in the wall separating the main cylinder 6 from the supplementary cylinder 7. The said sleeve 24 is also provided with an intake port 26, at right angles to said pressure port 25, and registering with an intake port 27, in the wall of the supplemental cylinder 7, said intake port 27 connecting by means of a manifold 28 with a Suitable carburetor, not shown. The sleeve 24 reciprocates in the cylinder 6, without any rotary motion therein, and passes up into the annular space 15. The above described projection 14 does not touch the inner side of the sleeve 24 and therefore permits the air in the said annular space to pass down therefrom as the sleeve moves up into the said space. The sleeve 24 is actuated by means of a cam 5, on the shaft 1, said cam operating between two parallel surfaces 29, in the frame 3() secured to the said sleeve 24. The form of the cam 5 is suoll as to give an intermittent motion to the sleeve 24, said sleeve moving rapidly from its lowermost to its uppermost posi-- tions and then remaining stationary in such positions before returning to its first position, all of which is hereinafter described. A supplementary piston 31 is mounted within the sleeve 24 and is connected to the second crank 4 by means of a connecting rod 32. This piston 31 is of usual construction and extends up into a position closely adjacent to the lower end of the projection 14 when it is at the upper end of its stroke. The length of stroke of this piston 31 lis preferably the same as that of the mam piston 16.

It is, of course, understood that the several pistons 16 and 31 and the sleeve 24 are providedl with suitable piston rings, it belng preferred that such rings, of the piston 16 and of the sleeve 24, as pass the several ports 21, 23, and 27, shall be slightly wider than the length of the said ports.

Referring particularly to Fig. 4, it will be seen that the cam 5, mounted on the shaft 1, is of special shape and is in constant engagement with both the upper and lower parallel surfaces 29,. of the cam frame 30, and that, therefore, the said cam frame, andthe sleeve 24 attached thereto, have a positive movement in the engine. The special form of this cam 5vis suoli that, in every complete turn of the shaft 1, the said frame 30 is stationary at the upper and lower ends of its stroke and that the upward and downward strokes occur through the intervening portions of turn of the said shaft 1. Therefore said sleeve 24 is stationary throughout two periods for each revolution of the shaft.

The cain 5 is made up of the arcs of circles whose centers are arranged at the angles of an equilateral triangle, one said center being positioned at the central axis of the shaft 1 and the other two centers being distant therefrom a distance equal to the stroke of the sleeve 24. The shape of the cam is obtained by extending the sides of the said equilateral triangle in both directions a distance equal to the side of the triangle and joining the ends of said extended lines by the arcs of circles from each such center, thus forming three long curved surfaces, each covering 60, said surfaces being joined together by the arcs of three small circles, each positioned diametrically opposite to the said long curves. Since these curves are all portions of circular arcs it is evident that the distance between any two parallel tangents of the cam is equal to the distance between the parallel surfaces 29 and is a constant value, since it is always made up of a long and a short radius through one of the three centers above described.

It will be observed that the port 25 in the sleeve 24, as well as the several ports 19 and 2O in the cuff or wall 18 of the main piston 16, are all provided with beveled upper and lower ends as clearly shown in the drawings and also that the upper surface of the supplleilnental piston 31 is correspondingly beve ec.

By referring to Figs. 4 and 5 it will be seen that the ports 25 and 26 in the sleeve 24 are at the same lever, but it will be understood that the pressure port 23 and the intake port 27 are at different levels, The

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r cylinder 6.

port 23 registers with the port 25 of the sleeve when the sleeve is at the upper end of its stroke while the port 27 registers with the port 26 of the Sleeve 24 when the sleeve Iis at the lower end of its stroke, and that when one said port is open the other' port is closed.

In Figs. 1, 2, 3, and 4 the parts of the engine are shown in simultaneous relative positions, In this instance the supplemental piston 31 is in the upper end of its stroke; the sleeve 24, in which it works, has already moved downward one-quarter of its stroke; and the main piston 16 is moving upward and still has three-eights of its stroke to travel before reaching its uppermost position. In this position the sleeve 24 has closed the intake port 27, of the supplemental cylinder 7 (Fig. 3), but the pressure port 25 is still in connection with the pressure port 23 leading to the main cylinder 6. Also in this position the opening 20, in the cuff 18 of the main piston 16, is still in connection with the pressure port 23 of the said And, as shown in Fig. 2, it is clear that the exhaust openings 19, of the cuff 18, are out of connection with the exhaust ports 21 of the cylinder 6. Therefore in this position, as shown in Figs. 1-4, the explosive mixture, which has been compressed in the sleeve 24 and the annular space 15, by the piston 31, has been forced, through the port 25 in the sleeve 24, the pressure port 23 in the cylinder 6 and the opening 2O in the cuff 18, into the explosion chamber formed by the interior of the cuff 18 and the annular space 11. And, since said piston 16 is still moving upward, the said connection between the opening 20 and pressure port 23 is about to be closed and the explosive mixture in the cylinder 6 will thus be further compressed until the piston reaches the upper end of its stroke.

When the piston 16 is at the upper end of its stroke the sleeve 24 is stationary, and at the lower end of its stroke and, therefore, the pressure port 23 of the cylinder'6 is closed thereby and, therefore, the pressure within the upper end of the cylinder 6, due to the explosion therein, cannot escape through the said pressure port 23, even when the opening 20 therein registers therewith, as the said piston 16 passes downward. It will be seen from Figs. 1 and 2 that the exhaust ports 21 of the cylinder 6 lie at a lower level than the pressure port 23, but that the exhaust and inlet openings 19 and 20, in the cuff 18 of the piston 16, lie in the same level and, therefore, no connection is made with the exhaust passage 22 until the said openings 19 register with the exhaust ports 21 at the lower end of the stroke of the main piston 16.

Referring back now to the same positions of the parts as shown in Figs. 1, 3, and 4, it

will be observed that the sleeve 24 is moving rapidly downward and that the pressure port 25 therein is about to close its connection with the pressure port 23, through the wall of the cylinder 6, and thatthe supplemental piston 31 is about' to start its downward, stroke. As the connection between the pressure ports 23 and 25 is thus closed, the downward motion of the supplemental piston 31 produces a partialvvacuum, in the upper end of the sleeve 24, until the intake port 26 registers with the intake port 27 in the cylinder 7. As soon as this connect-ion has been made the explosive mixture from the carburetor is drawn into the upper end of the cylinder 7 by the vacuum therein and by the further motion of the supplemental piston 31. r

The sleeve 24 remains stationary at the lower end of its stroke during most of the downward stroke of the piston 31, thus holding the intake port 26 in registering position with the intake port 27. The said sleeve 24 begins its upward stroke just before said piston 31 reaches the'lowest point in its stroke.

The said sleeve then cuts off the connection between the intake ports 26 and 27 as, or very shortly after, the piston 31 starts upward. The piston 31 and the sleeve 24 then travel upward together and compress the explosive mixture, now contained in the space between the plug 13 and the piston 31, until the pressure port 25 registers with the pressure port 23, at which point the sleeve 24 ceases'to move upward and the piston 31 continues its upward stroke.

Meantime,'during the downward stroke of the piston 31, the main piston 16 has been compressing the explosive mixture in the cuila 18 until it reaches the upper end of its stroke, when the charge is ignited, and the piston 16 is driven forcibly downward to rotate the shaft 1. The explosion occurs when the supplemental piston 31 is about three-eighths of its stroke downward and the sleeve 24 has substantially reached the lower end of its stroke. During the working or expansion stroke of the piston 16 the sleeve 24 first remains stationary at the lower end of its stroke, when the intake ports 26 and 27 are open, as above described, and then the exhaust openings 19, in the cud 18, register with the exhaust ports 21, to relieve the pressure in the cylinder 6 and to exhaust the gases through the manifolds 22 at the lower end of the stroke of the said piston 16. At this point the sleeve 24 has passed upward and reached its highest position and the pressure ports 23 and 25 register and the piston 31 continues to compress the gases in the supplemental cylinder 7. The main piston 16 then begins to rise and closes the exhaust ports 19 and 21 andl shortly afterwards the upper end of the inlet opening 20 communi-v Gates with the lower end ofthe pressure port 23 and admits the gases, which have been compressed in the cylinder 7, through the ports 25, and 23, and opening 20, into the upper end of the cylinder 6, and these gases are further compressed by both the pistons 16 and 3l until the opening 2O is out of register with the pressure port 23, when the gases are further compressed in the cylinder 6 by the piston 1G alone.

rlhus it will be seen that my improved engine makes one explosion for each revolution of the shaft, for each working cylinder, and that the explosive gases admitted to such wo-rking cylinder are highly compressed before the explosion takes place, and that therefore the thermodynamic eciency of the engine is high.

Having thus described my invention what I claim is 1. In an internal combustion engine, a working cylinder; a supplemental cylinder; a sleeve in said supplemental cylinder; a main piston in said working cylinder; a supplemental piston in said sleeve; an intake port in the supplemental cylinder; a pressure port joining the supplemental cylinderwith the main cylinder; ports in said sleeve adapted to register with the pressure port in said supplemental cylinder at the upper end of the stroke of the sleeve and with the intake port of said supplemental cylinder at the lower end of its stroke; an exhaust port in said working cylinder; two sets of ports in said working piston, one adapted to connect withthe pressure port and the other with the exhaust port, said piston ports being adapted to connect alternately with said cylinder ports; a shaft; means connect-ing said shaft with both said pistons whereby the relative position of the supplemental piston is in advance of the working piston; and means connecting said shaft with said sleeve and comprising a Ycam mounted .on said shaft together with a pair of parallel surfaces connected to said sleeve and both of which are continuously engaged by said cam; whereby said cam is adapted to hold said sleeve stationary an appreciable time at the upper and lower ends of its stroke, and whereby said sleeve is moved from one stationary position to the other at a high speed.

2. In an internal combustion engine7 a working cylinder; a supplemental cylinder; a sleeve in said supplemental cylinder; a main piston in said Working cylinder; a supplemental piston in said sleeve; an intake port in the supplemental cylinder; a pressure port joining the supplemental cylinder with the main cylinder; ports in said sleeve adapted to register with the pressure port in said supplemental cylinder at the upper end of the stroke of the sleeve and with the intake port of said supplemental cylinder at the lower end of its stroke; an exhaust port in said working cylinder; two sets of ports in said working piston; one adapted to connect with the pressure port and the other with the eX- haust port, said piston ports being' adapted to connect alternately with said cylinder ports; a shaft; means connecting said shaft with both said pistons whereby the relative position of the supplemental piston is in advance of the working piston; and means connecting said shaft with said sleeve and comprising an equilateral cam whose sides are formed of arcs orawn from radii from three mutually equidistant centers, together with a pair of parallel surfaces formed on an extension of said sleeve and both of which are continuously engaged by said cam, whereby the sleeve is positively held stati-onary an appreciable time at the upper and lower ends of its stroke, and whereby it is moved from one stationary position to the other ata high speed.

OSCAR H. ERICKSON i 

